Idiopathic pulmonary fibrosis is a fibroproliferative disorder characterized histopathologically by heterogenous interstitial fibrosis with fibroblastic foci and honeycomb lung. The diagnosis is based on a pluridisciplinary approach, integrating the clinical evaluation, the chest high-resolution computerized tomography features, and the pathological pattern of usual interstitial pneumonia on video-thoracoscopic lung biopsy when performed. When the tomodensitometric pattern is typical (50% of the cases), the diagnosis may be made without a lung biopsy. No treatment has proven benefit in survival. Treatment with N-acetylcysteine in association with corticosteroids and azathioprine has recently shown a modest functional improvement. Clinical trials are strongly needed in this still uncurable disease with median survival at 3 years of only about 50%.